The 1984 film Ghostbusters was released nationwide 30 years ago today. We know now what a global blockbuster it became, but at the time it was far from a guaranteed hit. A big budget special effects comedy? No one in Hollywood had heard of such a thing. Sure, it had the guys from SNL, who’d already shown their talents in Animal House, Caddyshack, The Blues Brothers, and Stripes, but compared to the Ghostbusters project those movies cost next to nothing to produce.

One of the leads for whom the script was written unceremoniously died of a drug overdose. The screenplay called for scores of special effects, and the major effects operations in town were tied up with other projects. To top it off, the Ghostbusters team was given a mere year to re-write, shoot, and edit the movie—even though none of the principals had ever attempted a project of that scale before. “The wisdom in town was that I had made a terrible mistake,” says former Columbia chairman Frank Price, who greenlighted the project.

The story of how Ghostbusters ever got made is a saga in itself. Bill Murray didn’t commit until the last minute, the script was re-written over and over, John Beushi died, John Candy didn’t work out, and all the special effects studios were busy with Star Wars and Indiana Jones movies. But somehow the supernatural special effects comedy Ghostbusters got made. Dan Aykroyd and Ivan Reitman tell the story in an article at Vanity Fair. -via reddit